Field of the Invention
The invention relates to a method for network communication, in particular for communication within an electrical low-voltage network. The invention also relates to a network which can be used for communication.
In a network which can be used for communication and in which the communication takes place via heavily attenuated media with interference that varies with time, adaptive and self-learning communication software is normally used, which is based on the mechanisms of collision identification and/or collision avoidance. Such mechanisms are, however, unsuitable for so-called PLC communication (PLC=Power Line Carrier) in a power supply network, since two terminal devices can transmit on different cables without being able to "listen" to one another. The use of a master-slave architecture is thus preferred for PLC communication or transmission in power supply networks, wherein a status check or status inquiry (status polling) is transmitted from the master to a number of slaves in a number of network paths.
A network which can be used for communication and has such a master-slave architecture is disclosed, for example, in the Published European Patent Application EP 0 598 297 A2. In this case, the master uses the network to send a logon request to all the newly installed devices (slaves) in the network, so that, after receiving a response from the newly installed slaves, the master can communicate with these slaves. Such a network, which can be used for communication, makes it possible, in particular, to read electricity meters and to automatically identify an additional meter or device connected to the network, without any additional installation cost. However, it is disadvantageous that only slaves (devices) which can be accessed directly by the master can be identified and can be included in the network.
Swiss Patent CH 677 300 A5 discloses a method for transmitting data packets in a network, in which subscriber stations which cannot be accessed directly by the master are contacted via subscriber stations which act as a relay station. In order to include new subscribers in the network, a special request is sent, which, if necessary, is sent via the relay stations to the new subscribers. The new subscribers then respond to the request from the master. Published German Patent Application DE 36 19 906 A1 and Published European Patent Application EP 0 395 495 disclose other networks, in which subscribers can be accessed indirectly.
International Publication Number WO 95/01030 also discloses a method of checking indirectly accessible slaves by a master via neighboring router slaves within a network, wherein the corresponding network route is defined by the master, and this master assigns a corresponding network address to the corresponding slaves.